Solved : CWP Roundcube Login Problem [ Connection to storage server failed ]

I'm getting problem after CWP mail server migration from existing server to new server. It's showing  Connection to storage server failed ,

General Troubleshooting Tips

• Run “postfix check” to make Postfix look for obvious configuration errors. If it returns no output then no problem was found.
• Read your /var/log/dovecot.log & /var/log/mail.log and look for warnings and errors.

I'm getting the following information from /var/log/dovecot.log

I get “Permission denied” from Dovecot in the mail.log file. You have the permissions wrong.

Run the following command

# chown -R vmail:mail /var/vmail

Finally all user's of that domain can login successfully .
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